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Plasmonic nano-aperture label-free imaging (PANORAMA)
Nareg Ohannesian1, Ibrahim Misbah1, Steven H Lin2
1Department of Electrical and Computer Engineering, University of Houston, 4800 Calhoun Road, Houston, TX, 77204, USA.
Nature Communications
|November 17, 2020
Summary
We developed PANORAMA, a novel label-free optical imaging technique for detecting nanoscale objects. This method achieves diffraction-limited resolution and high surface sensitivity without lasers, enabling precise nanoparticle detection and sizing.
Area of Science:
- Nanotechnology
- Optical Imaging
- Plasmonics
Background:
- Label-free optical imaging of nanoscale objects presents significant challenges.
- Existing techniques like surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR) have limitations in resolution and sensitivity.
- Current LSPR imaging methods often suffer from low light throughput and limited imaging capacity.
Purpose of the Study:
- To introduce a new label-free optical imaging technique, PANORAMA (PlAsmonic NanO-apeRture lAbel-free iMAging).
- To demonstrate PANORAMA's capability in detecting sub-100 nm dielectric nanoparticles with high resolution and sensitivity.
- To showcase PANORAMA's potential for parallel detection, counting, sizing, and dynamic monitoring of nanoparticles.
Main Methods:
- Utilizing ultra-near-field index modulation with plasmonic nano-apertures.
- Employing unscattered light for detection, compatible with standard bright-field microscopy setups.
- Implementing a system requiring only a lamp and camera, without lasers or interferometry.
Main Results:
- Achieved diffraction-limited resolution in imaging nanoscale objects.
- Demonstrated higher surface sensitivity compared to existing methods.
- Successfully detected, counted, and sized individual dielectric nanoparticles down to 25 nm.
- Enabled dynamic monitoring of nanoparticle distance to the plasmonic surface at millisecond timescales.
Conclusions:
- PANORAMA offers a breakthrough in label-free nanoscale imaging, overcoming limitations of SPR and LSPR techniques.
- The technique provides superior resolution, sensitivity, and imaging capacity using a simple, accessible setup.
- PANORAMA facilitates parallel, high-throughput analysis and real-time monitoring of nanoparticles.
